Commonly owned and related U.S. Pat. No. 5,614,269 discloses a method of making a water absorptive article comprising a water absorptive, water insoluble polymer and discloses the use of such a water absorptive article to protect cable, such as fiber optic cable, from water from the ingress of moisture and water into the cable. As explained in U.S. Pat. No. 5,614,269 ingress of water into cable is a substantial and persistent problem in the cable industry. Such ingress often results from changes in ambient conditions which cause differences in vapor pressure between the inside and the outside of a cable jacket. Consequently, moisture tends to diffuse in a unidirectional manner from the outside of the cable to the inside of the cable, resulting in an undesirably high moisture level inside the cable. High levels of condensed moisture inside a cable sheath system may have a detrimental effect on the transmission characteristics of a metallic conductor cable.
Furthermore, water may enter the cable as a result of damage to the cable which perforates the external water barrier elements. For example, animal attacks and mechanical impacts often create openings in the sheath system of the cable, which allows water to enter the cable. Once inside the cable sheath system, the water tends to move longitudinally along the cable into splice closures, if not controlled.
In another field, water flow through ground (meaning "earth") can pose problems, if not controlled. Water naturally percolates through the ground and such percolation is normally desirable because it purifies water. Rain water normally percolates through the surface of the ground and eventually flows into the local ground water system.
It is desirable to prevent percolation of water through ground in some instances. For example, it is desirable to prevent water egress from waste disposal sites into the adjacent ground and water ingress into waste disposal sites from the adjacent ground to avoid contamination of the local ground water by toxins in the waste disposal site. A landfill is a specific example of such a waste disposal site.
Bentonite clay has been used to block water flow into and out of waste disposal sites, but bentonite clay tends to migrate during use, leaving water permeable areas, and is heavy and therefore expensive to transport.
Accordingly, in addition to controlling water ingress into cables, there is also a need to control water flow through the ground, and there is a particular need to control water egress from a waste disposal site into the adjacent ground and water ingress from the adjacent ground into the waste disposal site.